Vascular Rings - Slings

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1. Complete Rings

Double Aortic Arch

Right arch dominant

Left arch dominant

Balanced

Right arch/Left ligamentum

Retroesophageal L subclavian

Mirror image branching

Right Arch Dominant
Left Arch Dominant
Right Arch/ Left Ligamentum

2. Incomplete Rings

Innominate artery compression syndrome

Pulmonary artery sling (RPA off LPA behind trachea)

Left arch/aberrant R subclavian artery

Left Arch/aberrant R subclavian artery

3. Clinical Symptoms

Present in first 6 months

Respiratory distress, stridor, cough, dysphagia

Early presentation in double arch

Apnea - innominate artery tracheal compression

4. Diagnostic Studies

Chest x-ray - arch location, tracheal compression

Barium swallow - posterior indentation

Sling - anterior indentation

MRI - definitive study

Bronchoscopy - innominate artery/pulmonary sling

Radiograph

5. Operation Double Aortic Arch

Left thoracotomy

Divide ligamentum

Divide and oversew lesser of 2 arches

Divide adhesive bands

Double Aortic Arch

6. Operation Right Arch/Left Ligamentum

Left thoracotomy

Divide ligamentum

Kommerell's diverticulum to chest wall

Righ Arch/ Left Ligamentum

7. Operation Innominate Artery Compression - Suspension

Right thoracotomy

Resect thymus

Suspend innominate artery to sternum

Post-operative bronchoscopy optional

Anatomical Orientation

8. Operation Innominate Artery Compression - Re-implantation

Optional operation

Moves origin so IA does not cross trachea

Anatomical Orientation

9. Operation Pulmonary Artery Sling

Median sternotomy

Cardiopulmonary bypass

Reimplant LPA into main PA

LPA anterior to trachea

Tracheoplasty for complete rings

Anatomical Orientation

10. Results Pulmonary Artery Sling

Op mortality < 0% rings/IA compression

Op mortality 10-20% PA sling

Permanent relief of symptoms >90%

Patency of PA sling >90%

Tracheoplasty long-term results unknown

11. Summary

High suspicion based on symptoms

Chest x-ray, MRI, Barium esophagram

Operative approach based on anatomy

Symptoms relieved in 90%

EXTENDED OUTLINE I. Classification

- Double Aortic Arch

- Right Arch with left ligament

- Left Arch with arch vessel anomalies

- PA sling

II. Embryology

A. Complete Ring

1. Double Aortic Arch (DAA)

- Right dominant (70%), Left dominant (20%), and balanced (10%)

- persistence of R 4th arch

- R CCA & SCA off the R arch

- L CCA & SCA off the L arch

- R arch is usually dominant and travels posteriorly to the esophagus to join the descending aorta

2. Right Arch with left ligament

- persistence of R arch with involution of the L between the L CCA & the L SCA

- Retroesophageal L SCA (65%), or mirror image branching (35%)

- Kommerrell's diverticulum may be present at the base of the SCA

B. Incomplete Ring

1. L Arch with aberrant R SCA

- secondary to regression of the R arch between the R CCA & R SCA

- aberrant R SCA deforms the esophagus posteriorly

- most common arch anomaly (incidence of 0.5%), but is not a complete vascular ring

2. L Arch with aberrant innominate

- leftward and posterior displacement of the innominate on the arch

- anterior compression of the trachea

3. PA Sling

- L lung captures the arterial supply from the R 6th arch instead of the L 6th arch

- origin of the L PA off the R PA

- courses between the trachea and the esophagus causing anterior compression of the esophagus

- associated with tracheobronchial malacia and complete tracheal rings

- associated with intracardiac defects

III. Presentation

- symptoms secondary to compressive effects of on the trachea and the esophagus

- occasional stridor, brassy cough, misdiagnosed asthma, frequent URI's

- dysphagia less common and presents as infant progresses from liquids to solids

-with innominate artery compression 1/2 have apneic spells

IV. Diagnosis

CXR - diagnosis a R arch

Barium swallow - indentation of the esophagus

- DAA or R arch with L ligamentum have a deep posterior indentation

- R arch with aberrant L SCA has an oblique posterior indentation

Angiogram - rarely needed

Bronchoscopy/Bronchography - especially needed with PA sling

MRI/CT - very good at defining anatomy

- " 4 artery sign" - 2 SCA's and 2 CCA encircling the trachea

- disadvantage of not visualizing nonvascular structures

V. Treatment

A. General

1. all symptomatic patients ASAP

2. Asymptomatic patients

- complete ring - elective repair

- incomplete ring - follow clinically

B. Double Arch

1. Left posteriolateral thoracotomy

2. divide the smaller of the two arches

- usually between the CCA and the SCA

3. ligate the duct and fibrous tissue being careful of the recurrent laryngeal nerve

C. R Arch with L Ligamentum

1. Left posteriolateral thoracotomy

2. Divide the ligament

3. Kommorrell's diverticulum, pex or resect

D. L Arch with aberrant R SCA

1. most are truly asymptomatic

2. Symptoms

- ligate R SCA in small children

- reimplant in most others

E. L Arch with aberrant innominate

1. suspend the arch to the posterior sternum

2. reimplant the innominate to the right and anterior on the arch

F. PA Sling

1. median sternotomy

2. address tracheomalacia the primary repair or pericardial patch

3. reimplant L PA on to the main PA

VI. Results

- up to 1/2 have abnormal flow on formal pulmonary testing at one year despite been asymptomatic

- noisy breathing may take awhile to resolve

- successful 95% of the time

- minimal morbidity except with PA Sling